Fix demote cmd message
Fix demote cmd message

Signed-off-by: Tonis Tiigi <c2470c48b2d3312d61f94f18d3a1cd113d1915ad@gmail.com>
yp-engineering/swarmkit,sungwonh/swarmkit,diogomonica/swarmkit,cezarsa/swarmkit,runshenzhu/swarmkit,dperny/swarmkit-1,runshenzhu/swarmkit,fate-grand-order/swarmkit,Noyan759/swarmkit,elifa/swarmkit,jlhawn/swarmkit,cezarsa/swarmkit,yp-engineering/swarmkit,jlhawn/swarmkit,elifa/swarmkit,yongtang/swarmkit,RenaudWasTaken/swarmkit,deljuven/swarmkit,vasil-yordanov/swarmkit,yongtang/swarmkit,allencloud/swarmkit,AliyunContainerService/swarmkit,Noyan759/swarmkit,sungwonh/swarmkit,cheyang/swarmkit,vasil-yordanov/swarmkit,AliyunContainerService/swarmkit,docker/swarmkit,allencloud/swarmkit,alyyousuf7/swarmkit,fate-grand-order/swarmkit,RenaudWasTaken/swarmkit,docker/swarmkit,aaronlehmann/swarmkit,cheyang/swarmkit,alyyousuf7/swarmkit,dperny/swarmkit-1,diogomonica/swarmkit,aaronlehmann/swarmkit,deljuven/swarmkit